It appears you go to a mechanic. Have him put the car on a lift. Take a good flashlight with you. Look from the top of the head down to the leak have him use rags and wipe it off if you can see the oil coming out. Then get a price to repair the leak.
A friend sold a car and the man came back and was concerned about a minor leak. He went to Auto Zone and got a couple bottles of stop leak. I think he got radiator stop leak. Two minutes after pouring it in the strainer on the oil pump plugged up. This then became a problem for the buyer and seller.